What To Know About Black Oxide Coating As a Surface Finish
The surface finishing process is a vital step in precision machining. Such a procedure increases a workpiece’s lifespan and aesthetics. However, dimensions increase in size upon using some of the surface finishes. But with black oxide, its finish remains distinct compared to others. The procedure bestows good properties with minimal extension dimensions. At Creatingway, we use the black coating process to better your project. Below is a further guide on what to know about the procedure.
How to Define Black Oxide Coating Process?
The black oxide coating belongs to the conversion coating category. Whereby the process uses a chemical process to make a coating. In this procedure, we dip workpieces in an alkaline solution. The iron on the metal workpiece surface converts to magnetite. The magnetite produces a black coating upon the surface of a metal. Some metals that use black oxide coating include; powdered metals, stainless steel, silver solder, zinc, and copper.
Steps Involved When Applying Black Oxide Finish
The procedure involves degreasing and cleaning the portion with an alkaline solution. Such a step prepares the workpiece for black oxide coating.
We Wash off the alkaline solution with distilled water. The main aim is to eliminate the excess solution used during cleansing.
If the parts have scales or rust, then this process is crucial. We soak the scaled pieces in acid to eliminate oxide stains and rusts.
The procedure is vital as it involves finished parts with blind holes. By washing the piece with an alkaline solution, we prevent bleed-outs. The bleed-outs impair the efficiency of the surface part.
The stage involves finished parts plated onto another material. Such material includes; cadmium, chromium, and zinc. It is essential to de-plate as the finish can’t stay on plated parts.
Applying Black Oxide Coating
The application is a significant step where it involves coat application. Workpieces get dipped into tanks that have alkaline solutions. Some of these solutions include; nitrates or sodium hydroxide.
The after-finish prevents corrosion that lowers the efficiency of a workpiece. However, some materials like brass or stainless steel don’t require the after the finish. The metals possess anti-corrosion properties, unlike other metals. The after-finish agents include; lacquer, oil, and wax. We use lacquer since it’s easy to use and dries quickly.
What Are Forms of Black Oxide Finish?
Cold Black Oxide Coating
The process involves depositing copper Selenide at 68-86 Fahrenheit. After various testing, the coat isn’t resistant to wear compared to others. So, applying the after-finish helps boost the corrosion resistance of the coat.
Hot Black Oxide Finish
This form of the coat is the most common type of all. Where the finish parts get dipped in salt baths of high temperatures. The salt baths contain; nitrates and caustic soda. The required temperatures must remain in place since lower temperatures delay the procedure. High temperatures facilitate rusting.
Mid-temperature Black Oxide Finish
The procedure is similar to hot black oxide coating but differs in temperature. The required operating temperature is 194-248 Fahrenheit range. With such a range, conversion of metal to magnetite is possible. The major advantage of this process is that it doesn’t produce caustic fumes like the hot black oxide coating process.
Applications of Black Oxide Finish
Most automotive parts use black oxide finishes. Some features include; spark plugs, filter cans, brake valves, and suspension bushings.
The light absorbing properties enables its usage in X-ray machines. Doctors obtain a better view of the inner human anatomy with such imaging.
Some parts like shotgun shells and magazines are really on black oxide coating. Specifically, the mid-temperature black oxide best suits military hardware. Other military features include; turrets of military Humvees.
Examples of electrical parts using black oxide coating include; cutters, gears of timers, and wire strippers.
During Manufacturing Assemblies, the precision tools used have black oxide finishes. Some of the tools include; fasteners, bearings, and gauges.
Considering Factors While using Black Oxide Finish
The lifespan of the black oxide finish is superb. The primary reason being it has rust-preventing qualities. Depending on the customers’ wants, such a factor relies on the application and the area used.
The location To Be Used
Depending on the location, the lifespan varies greatly. The finish has a more long-lasting effect indoors than on the outer parts. Since the outer parts are prone to high temperatures and humidity, such conditions wear off black oxide faster, reducing efficiency.
The Desired look
In terms of aesthetics, it is very crucial in the final appearance. By using black oxide coating, we obtain two last looks. These looks include; glossy and matte. Manufacturers use either of the two, depending on the customers’ wants—all to better your project.
Currently, the black oxide coating is very common in our CNC machining products, metal sheet products, and more. It can make the appearance of our products better, and make our products durable when we will make sandblasting together. So now, more and more customers like to make this coating for most of aluminum material products.
In Conclusion, Creatingway uses different kinds of surface finish. The application of these finishes depends on our customers’ desires. Kindly choose Creatingway while dealing with products that require a black oxide finish. In doing so, you’ll obtain satisfactory results.
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